There are a ton of bugs in Heart of fear! (sorry i had to..)
We had a similar issue in MV the first week, it took all kinds of scrambling around and logging and resetting. It seemed we had 2 people who were "saved" to 0/6, but they could not be in the same instance. If one was in the group the other couldnt zone in. We ultimately all logged out reset the instance, prayed, did a few dances and killed some alliance (sacrifices) and it worked.